Methods for substituting a halogen atom or a sulfonyloxy group to a fluorine atom by reacting a compound subjected to the nucleophilic substitution reaction such as a halogenated compound or a sulfonate with potassium fluoride as a fluorinating agent have been known (e.g. patent document 1, patent document 2, non-patent document 1, non-patent document 2 and non-patent document 3).
A method for using a quaternary ammonium fluoride as a fluorinating agent (e.g. non-patent document 4) and a method for using a quaternary ammonium fluoride in combination with cesium fluoride (e.g. non-patent document 5) have been known. Further, methods for using a quaternary ammonium bifluoride or a quaternary phosphonium bifluoride, which contains hydrogen fluoride and is synthesized using a highly corrosive and toxic hydrofluoric acid, have been known (e.g. non-patent document 6, patent documents 3 and 4).
Patent document 1: WO02/092608
Patent document 2: WO03/076366
Patent document 3: JP 61-161224 A
Patent document 4: JP 4-124146 A
Non-patent document 1: J. Amer. Chem. Soc., 78, 6034 (1956)
Non-patent document 2: Chemistry Lett., 761 (1981)
Non-patent document 3: Synthsis, 920 (1987)
Non-patent document 4: J. Org. Chem., 49, 3216 (1984)
Non-patent document 5: Synthetic Commun., 18, 1661 (1988)
Non-patent document 6: Tetrahedron Lett., 28, 4733 (1987)
It has been known that 1-ethyl-3-methylimidazolium fluoride as an electrolyte raw material is obtained by reacting a methanol solution of the corresponding imidazolium carbonate with ammonium fluoride or with potassium fluoride in water solvent (e.g. non-patent document 8 and patent document 5). Further, a method for obtaining 1-ethyl-3-methylimidazolium fluoride as the hydrogen fluoride adduct by reacting 1-ethyl-3-methylimidazolium chloride with hydrogen fluoride has been known (e.g. non-patent document 7). It has been known that 1-butyl-3-methylimidazolium fluoride hydrate is produced by pyrolyzing 1-butyl-3-methylimidazolium fluoride hexafluorophosphate (e.g. non-patent document 9).
Patent document 5: JP 2003-335734 A
Non-patent document 7: J. Fluorine. Chem., 99, 1 (1999)
Non-patent document 8: Electrochemical and Solid-State Letters, 5(6) A119-A121 (2002)
Non-patent document 9: Green Chemistry, 2003, 5, 361-363